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lammps/lib/voro++/examples/degenerate/degenerate2.cc
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// Degenerate vertex example code
//
// Author : Chris H. Rycroft (LBL / UC Berkeley)
// Email : chr@alum.mit.edu
// Date : August 30th 2011
#include "voro++.hh"
using namespace voro;
const double pi=3.1415926535897932384626433832795;
// The total number of points to create as degenerate vertices
const int points=100;
// The number of planes that will be cut around each point
const int n=64;
const double step=2*pi/n;
// The angle (in radians) of the cutting planes from horizontal
const double theta=0.04;
// This function returns a random floating point number between 0 and 1
double rnd() {return double(rand())/RAND_MAX;}
int main() {
double x,y,z,rsq,r,phi;
voronoicell v;
int n=0;
// Initialize the Voronoi cell to be a cube of side length 2, centered on
// the origin
v.init(-1,1,-1,1,-1,1);
// Plane cutting
while(n<points) {
// Choose a random point
x=2*rnd()-1;
y=2*rnd()-1;
z=2*rnd()-1;
// Skip it if it's outside the unit sphere or too close to the
// origin
rsq=x*x+y*y+z*z;
if(rsq<0.01||rsq>1) continue;
// Rescale the point so that it has modulus 1, and then apply
// plane cuts around this point
r=1/sqrt(rsq);x*=r;y*=r;z*=r;
rsq=sqrt(x*x+y*y);r=z/rsq;
for(phi=rnd()*step;phi<2*pi;phi+=step)
v.plane(x*cos(theta)+sin(theta)*(-y*cos(phi)/rsq-x*r*sin(phi)),
y*cos(theta)+sin(theta)*(x*cos(phi)/rsq-y*r*sin(phi)),
z*cos(theta)+sin(theta)*rsq*sin(phi),1);
n++;
}
// Output the Voronoi cell to a file in Gnuplot format
v.draw_gnuplot(0,0,0,"degenerate2.gnu");
// Optional POV-Ray output
v.draw_pov(0,0,0,"degenerate2_v.pov");
v.draw_pov_mesh(0,0,0,"degenerate2_m.pov");
}
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